Fig. 1. Sequence, structure and expression of Xenopus Sox9. (A) Deduced amino acid sequence from Xenopus, human, mouse, chicken, alligator and zebrafish Sox9 were aligned using Mac Vector CustalW Alignment. Identical and similar amino acids are in black and gray boxes, respectively. Conserved regions in human and chicken Sox9 sequences selected to design degenerate primers are indicated in green. The HMG box is underlined in blue. The peptide corresponding to the C terminus of human Sox9 used to generate rabbit antibodies against Sox9 (Bridgewater et al., 1998) is underlined in red. (B) Northern hybridization analysis. Developmental expression of Sox9 mRNA. Stages are according to Nieuwkoop and Faber (Nieuwkoop and Faber, 1967). Ethidium bromide-stained rRNAs are shown as loading control.